A Rapid Biological and Ecological Inventory and Assessment of the Cajon Bonito Watershed, Sonora, Mexico. Part 1: Natural History

Abstract

Cajon Bonito is a perennial stream that drains the western watershed of the Sierra San Luis, Sonora, Mexico. The Sierra San Luis is one of dozens of mountain ranges that are referred to as "sky islands" in a region called the Madrean Archipelago. This landscape exhibits an enormous array of habitats and environments that has made it one of the "mega-biodiverse regions" of the planet. I discuss the unique setting and qualities that make Cajon Bonito one of the most crucial and robust corridors in this sky island archipelago. The information and data that support this conclusion were gathered using a unique set of protocols and field methodologies referred to as Rapid Inventory and Assessment (RAP). I have modified a plant species inventory field method, the variable transect, that was developed for use in the tropics, and I have applied it in the habitats of the Southwest. I have also streamlined the method so that it can be used by a single observer instead of a team. Use of this method in the Cajon Bonito watershed provided me with a quick source of raw, multi-dimensional sampling data. It also provided a wealth of non-quantitative environmental information that reveals the study site's rich natural history.